Milking device provided with cleansing means

ABSTRACT

Device for pneumatically milking a cow, comprising a number of milk extractors, each comprising a teat cup as well as milk line connected to the lower end of the teat cup, which line leads from the teat cup to a collection chamber for the milk from the teat cup, each milk extractor being provided with a supply for a cleansing medium, such as a disinfectant, to the teat cup, in particular to a teat present in the teat cup, the supply comprising a line having an end portion with discharge end, and each milk extractor being provided with means for closing off the passage of the milk extraction at or downstream of the discharge end of the line for cleansing medium, preferably at that level, when discharging the cleansing medium, the closing means comprising a reciprocating closing body that can be moved between a position leaving the passage of the milk extractor free and a position closing it off, the closing body being provided with a squirt line forming the end portion with discharge end of the line for supply of cleansing medium, and being positioned to debouch into the milk extractor, particularly the milk line, when in the closing-off position.

This application is a divisional of application Ser. No. 10/393,431filed Mar. 20, 2003.

The invention relates to a milking device provided with cleansing means,in particular for cleansing/disinfecting the teat to which the milkingdevice is connected.

From German patent application 26 22 794 such a device and method areknown. This document shows a milking device for pneumatically milking acow and subsequent cleansing or disinfecting the teats of the cow'sudder, with a system of four milk extractors, each comprising a teat cupwhich at one end is provided with an open lining and with the other endis connected to a milk line to a common milk collection chamber for themilk from the cow in question, each cup having a connection to a sourceof changing vacuum, and an outflow opening of a line for the supply ofcleansing liquid being arranged in the wall of a teat cup.

When using this known device the method used is to first place the teatcups around the cow's teats, after which the cow is milked by means ofthe changing vacuum. After finishing milking the cow, while the cow'steats are still in the teat cups, a certain quantity of cleansing liquidis squirted into the teat cup by means of a pump. Said liquid willdisinfect the teat and the space in the teat cup, but will subsequentlytogether with the milk residue in the teat cup deposit on the inner wallof the teat cup. The liquid will then have the chance, even before theteat cups have been removed from the teats, to go back past the innerwall or from the teat back down and thus partially end up in the milkline. As a result milk residues of a cow will not only be left in theteat cup and milk line but will thus also transfer a contamination fromthe one cow to the other.

Moreover, when milking the next cow residues of the cleansing liquidthat have ended up in the milk line will subsequently end up in thecentral milk storage to which it is connected and therefore in the milkto be delivered.

A number of suggestions for improvements of this have been described inapplicant's earlier International patent application WO 99/66787. Inboth of these suggestions use is made of a leaf spring, which in theunloaded situation abuts the inner surface of the milk extractor andthen closes off a supply chamber for cleansing medium, and which in aloaded situation closes off the passage in the milk extractor to thedownstream portion thereof and clears the way for supplied pressurized(by compressed air) cleansing medium. In that way when discharging acleansing medium, and the aforementioned problem therefore exists, it iscounteracted that during discharging the cleansing medium said mediummay end up in the milk line and thus in the milk collection chamber. Ina first embodiment, the spring leaf is operated by means of a pusher,which is connected to a separate pressure line.

In a second embodiment, which is simpler as to construction, the leafspring is directly operated by the pressure of the cleansing mediumitself.

It is an object of the invention to improve on this.

A further object of the invention is to provide a milking device, withwhich in a reliable or positive manner a closure can be realised andmaintained for and during discharging cleansing liquid in a milkextractor, particularly teat cup and contiguous line portion.

A further object of the invention is providing a milking device, withwhich it can almost entirely be ruled out that cleansing medium isdischarged before the closing of the passage is completed as a result ofwhich cleansing medium might otherwise end up in the milk.

A further object of the invention is a device of the kind mentioned inthe preamble with which in a reliable manner cleansing medium cannot bedischarged until the passage in the milk extractor is closed off.

At least one of these objects is achieved according to the inventionwith a device for pneumatically milking a cow, comprising a number ofmilk extractors, each comprising a teat cup as well as a milk lineconnected to the lower end of the teat cup, which leads from the teatcup to a collection chamber for the milk from the teat cups, each milkextractor being provided with a supply for a cleansing medium, such as adisinfectant, to the teat cup, in particular to a teat present in theteat cup, the supply comprising a line having an end portion withdischarge end, and each milk extractor being provided with means forclosing off the passage of the milk extractor at or downstream of thedischarge end of the line for cleansing medium, preferably at thatlevel, when discharging the cleansing medium, the closing meanscomprising a movable closing body that can be moved between a positionleaving the passage of the milk extractor free and a position closing itoff, the closing body being provided with a squirt line forming the endportion with discharge end of the line for supply of cleansing mediumand being positioned to debouch into the milk extractor, in particularthe milk line, when in the closing position.

By accommodating the end portion of the supply line of cleansing mediumin the closing body the mutual position of them both is fixed and known.With known movement of the closing body it can be ensured in a simplemanner by suitable selection of the location of the discharge opening ofthe squirt line that the discharge can take place at the correct momentwith, an actually closed off passage.

Preferably the device is provided with means for pneumatically movingthe body. The device may comprise a compressed air connection to thesupply line for the supply of cleansing medium. In an embodiment, saidcompressed air line may be used for the movement of the closing body. Inanother embodiment these functions may be separated, in two separatelyoperable pressure lines.

In a first further development of the device according to the inventionthe closing body is movable between the free position and a closingposition by means of a reciprocating movement.

A simple failure-free embodiment is one in which the closing body isformed by a—preferably free—piston that is bearing mounted in a slidingmanner in a chamber debouching in the milk extractor and preferably ispositioned transverse to it. A free piston is easy to manufacture andmount, and moreover takes up little length of place.

In case the piston is a free piston it can advantageously be provided atits inner end with a duct in which a fixed pin extends, the duct beingpart of the squirt line. The pin cannot only form a guidance means forthe piston, but also ensure a relative closing of the duct and thus thesquirt line during the (fast) pressure build-up in the end chamber andthe movement of the piston.

At its inner end the piston may be provided with a sealing for sealingagainst the inner surface of the chamber, a supply line for at leastcompressed air debouching in the chamber in its portion opposite theinner side of the piston. Alternatively or additionally the chamber nearthe connection to the milk extractor can be provided with a sealing forsealing engagement of the piston's circumference, at the side of thepiston facing away from the milk extractor. Thus pressure build-up andthe subsequent movement of the piston can take place in the chamber,without leakage of cleansing medium.

The piston may have a circular cross-section, the duct being arrangedeccentrically in the piston, as a result of which undesirable rotationof the piston (and thus of the discharge opening) is counteracted.Alternatively rotation of the piston may be prevented by using a pistonof a cross-section that is not round. The chamber and milk extractorpassages are then complementary fittingly formed.

The piston is arranged/indexed to always discharge the cleansing mediumin the correct direction when cleansing.

The device can also be used for rinsing the milk extractor, upstream ofthe closing of the milk line, when it is further provided with means forpassage of water, particularly in the form of a pulsating water/airmixture, through the supply line to the discharge end.

The piston may also have a narrowed portion, situated at radial distancefrom the inner surface of the chamber, the sealing provided at thechamber engaging about the narrowed piston portion. As a result a spaceis created which when necessary is easy to clean or rinse, as will beexplained later. Furthermore a space is created for a possible (coil)spring.

Preferably said sealing is a ring having a sealing lip oriented to thechamber inner side, as a result of which it is prevented that residuesof particularly the cleansing medium that are at the inner side of thesealing, are sucked towards the milk line during milking as a result ofthe pulsating vacuum in said line.

Preferably the discharge opening in the piston is substantially radiallyoriented, preferably in a direction substantially parallel to thepassage of the milk extractor and towards the teat cup.

In case the piston, in the retracted, free position, opens with thedischarge opening at the inner side of the sealing, and the sealing isactive around a piston end situated outside of it, it is prevented thatduring milking possible residues in the discharge opening are suckedinto the milk line.

Preferably the piston is provided with a recess, duct or the like, on aportion at the inner side of the discharge opening, for fluidcommunication in the closed-off position of the space in the milkextractor upstream of the closing body and the chamber. As a resultcleansing medium, that falls back onto the piston and—because of theclosing—cannot go further into the milk line, can run down to thechamber, which to that end preferably is provided with drainage holes.

In a simple constructive manner the recess can be a levelling in thesurface of the piston.

It is further preferred that the milk extractor is provided with achamber for fitting accommodation of the end of the closing body in aposition completely closing off the milk extractor, so that it is oncemore additionally prevented that cleansing medium flows past the closingbody. Furthermore the milk extractor can be provided in the innersurface with means for guiding the closing body, so that the action ofthe piston is further improved.

In a further embodiment the device is furthermore provided with means,such as a spring, for biassing the closing body in the closing-off,cleansing position towards the free, milking position (also see above).Thus it can be ensured that the piston/the closing body moves back tothe starting position, in which the passage is free, particularlyimmediately after discharge of cleansing medium has been stopped.Alternatively use can be made of putting the line for the cleansingmedium on a vacuum.

In a first further development of the device according to the inventionthe pin has a passage for—preferably permanent—fluid communication ofthe duct to the supply line, the means for pneumatically moving the bodyalso being formed by a pressurized air or compressed air line separatefrom the supply line. It is then prevented that cleansing medium ends upat the inner side of the piston.

In an alternative further development the means for pneumatically movingthe body are also formed by the pressurized cleansing medium. When thesaid pin, but then without passage, is used, it may be shortened, sothat it closes off the duct in the piston in a first section and then nodischarge of cleansing medium from the squirt line takes place. When thepiston is in the closing position the pin will have come out of theopening of the duct, so that pressurised cleansing medium will gothrough the duct in the piston and will squirt out of the dischargeopening. It is preferred here that the discharge opening is situated atsuch a distance from the end of the closing body that it is not releasedin the passage of the milk extractor until the body has closed off thepassage of the milk extractor completely.

In an alternative embodiment the closing body is movable between thefree position and the closing-off position by a rotational movement. Theclosing body can then be provided with a milk passage which in the freeposition is in open line with the milk flow paths in the milk extractor.The rotation can take place about an own axis of the closing body,particularly transverse to the milk line.

From a further aspect the invention provides a device for milking a cow,comprising a number of milk extractors, each defining a milk passage andcomprising a teat cup as well as a milk line connected to the lower endof the teat cup, which line leads from the teat cup to a collectionchamber for the milk from the teat cups, each milk extractor beingprovided with a supply for a cleansing medium, such as a disinfectant,to the teat cup, in particular to a teat present in the teat cup, thesupply having a discharge nozzle, which is a part of a closing body forthe milk passage, which closing body is movable between a positionleaving the milk passage of the milk extractor free and a positionclosing it off, the discharge nozzle being positioned to debouch intothe milk extractor, in particular the milk line, when in the closingposition.

In all preceding embodiments the end portion of the discharge end or thedischarge nozzle can advantageously be positioned to be closed off fromeither the milk extractor or the milk passage when in the free position.

In a very simple and easy to place—also afterwards—embodiment, theclosing means are accommodated in a coupling piece which is accommodatedin the milk extractor, preferably near the transition between the teatcup and the (flexible) milk line.

The invention also relates to such a coupling piece, as well as to anassembly of a number of devices according to the invention and a centralmilk storage connected to the milk collection chamber.

From a further aspect the invention provides a method for milking a cow,the milk discharge being closed off after milking by moving a closingbody from a position keeping the milk discharge open to a positionkeeping the milk discharge closed off, cleansing medium being dischargedvia the closing body, by squirting in the milk discharge towards theteat cup, the teat cups being released, and while keeping the closingbody in the closed off position, squirting a pulsating water/air mixturevia the closing body for rinsing the milk extractor.

Preferably when the teat cups are still attached to the cow, in theclosed position of the closing body, cleansing medium falling back onthe closing body is deflected from the side of the closing body facingthe teat cup to a chamber, particularly a chamber in which the closingbody can be accommodated in the open position.

Preferably the closing body is subsequently moved to the open position,in which the chamber is sealed with respect to the milk discharge, andsubsequently a water/air mixture is discharged again via the closingbody, for rinsing the chamber, the rinsing liquid escaping via drainageholes.

Thus it is ensured with simple means that no residues of cleansingmedium are left behind.

From a further aspect the invention provides a device for pneumaticallymilking a cow, comprising a number of milk extractors, each comprising ateat cup as well as a milk line connected to the lower end of the teatcup, which line leads from the teat cup to a collection chamber for themilk from the teat cups, each milk extractor being provided with asupply for a cleansing medium, such as a disinfectant, to the teat cup,in particular to a teat present in the teat cup, the supply comprising aline debauching in the milk extractor, in particular the milk line, atthe location of a discharge end, and each milk extractor being providedwith means for closing off the passage of the milk extractor at ordownstream of the discharge end of the line for cleansing medium,preferably at that level, when discharging the cleansing medium, theclosing means comprising a reciprocating closing body which in thedischarge end can be moved between a position leaving the passage of themilk extractor free and a position closing it off, the closing bodybeing provided with a squirt line forming the end portion of the linefor the supply of cleansing medium.

Below the invention will be further elucidated on the basis of twoexemplary embodiments shown in the attached drawings, in which:

FIG. 1 is a device according to the invention arranged under a cow;

FIGS. 2A and 2B show cross-sections in isometric view of a firstembodiment of a coupling piece according to the invention, in themilking position and in the cleansing position, respectively; and

FIGS. 3A and 3B show cross-sections of a piston in the coupling piece ofthe FIGS. 2A and 2B, in the milking position and in the cleansingposition, respectively.

FIGS. 4A-C show a second embodiment of a coupling piece according to theinvention, a cross-section in disassembled situation, a detail of asealing ring in it, and a top view of the chamber part of the couplingpiece, respectively;

FIGS. 5A and 5B show the coupling piece of FIGS. 4A-C in milkingposition and cleansing position, respectively;

FIGS. 5C and 5D show the coupling piece of FIGS. 4A-C in milk linerinsing position and chamber rinsing position, respectively, and;

FIGS. 6A,B and 6C,D show a third possible embodiment of a coupling piecefor a device according to the invention, wherein the coupling piece isshown in the milking position and the cleansing position, respectively,in (partial) cross-sections in two longitudinal planes perpendicular toeach other.

FIG. 1 shows a cow of which only the hind legs have been drawn with anudder 2 and four teats 3, in which a device 1 according to the inventionhas been arranged under the teats 3 of the udder 2 of the cow.

The device 1 for pneumatically milking the cow comprises four milkextractors, which each comprise a teat cup 5 and a milk line 6, in whichbetween the teat cup 5 and the milk line 6 a coupling piece 4 accordingto the invention has been arranged. The milk lines 6 supply the milk toa milk collection chamber 7, from where the milk is transported to acentral storage via a common discharge line 25. Each teat cup 5 isconnected via a line 8 to a source of a changing vacuum, by means ofwhich the milking is carried out. Each coupling piece 4 is provided witha supply line 9, which is connected to a manifold 10 for cleansingliquid, such as iodine, which is supplied via a line 11. Via the line 12the air is supplied under pressure to the manifold 10 in order to blowthe liquid under the influence of the pressure of the air into the teatcup.

The coupling piece 4 shown in FIG. 2A has a housing 14 made of syntheticmaterial, having a connection end 16 to which the teat cup 5 can beconnected, and a discharge end 17, to which the milk line 6 can beconnected. The housing 14 forms a passage 15 for milk coming from thedirection A, so that it may continue flowing from the teat cup to themilk line 6.

The coupling piece 4 is provided with extension 18, in which a chamber19 is formed, in which a free piston 23 has been accommodated. Thechamber 19 has been provided with a connecting nipple 30 for the line 9.The piston 23 is straight circle-cylindrical and provided with a flatend 23 a and an inner end 23 b widened with flange 24. At the inner end23 b a duct opening 26 is situated eccentrically with respect to thecircle-cylindrical body of the piston 23, in which opening a pin 27extends, which with widened head 28 is secured in the wall 18 a. Theflange 24 leaves a slit space open with respect to the inner surface ofthe chamber 19.

Where the chamber 19 debouches in the passage 15 a ring shoulder 33 anda sealing ring 22 have been accommodated in the wall of the housing 14.Said sealing ring 22 sealingly engages the outer surface of the piston23, but makes movement along it possible.

As indicated in FIG. 3A the piston 23 is internally provided with a duct31 extending in axial direction, which duct near its bottom merges inradial direction in a little duct 32, which ends in discharge opening29. The eccentricity of the duct 31 and of the pin 27 is such that thedischarge opening 29 and the little duct 32 are oriented parallel to thecentre line of the passage 15, and will remain so. The pin 27 fits(very) snugly in the duct 31. When milking has ended and the teat cups 5are still around the teat of the cow, control means that are not furthershown pressurize the line 9 with a mixture of air and cleansing medium.Via connecting nipple 30 it (B) enters chamber 19, as considered in thedrawing below the flange 24. The connecting nipple 30 may alternativelyalso be arranged in the upper wall of the chamber 19 as considered inthe drawing, but the exemplary embodiment shown is more efficient in theuse of space and line length. The line 9 will after all first extendfrom below upwards.

The pressure prevailing in the line 9 will also be present at the innersurface 23 b of the piston 23. As a result the piston 23 will be slidout of the chamber 19. During the movement of the end 23 a transverselythrough the passage 15, the piston 23 is guided on both sides byguidance grooves 21 made in the wall of the housing 14. The movement ofthe piston 23 will take place very quickly, in which it should beconsidered that the pressure used could be approximately 5 Bar. Finallythe end 23 a end up in the cavity 20, in which it is accommodated in asnugly fitting manner. At that moment the pin 27 has come out of theduct 31. The surface of the smallest passage of the duct 31/little duct32 is smaller than the one of the nipple 30, so that no discharge willtake place before the piston 23 has moved out completely. The dischargeopening 29 has then just become exposed in the passage 15, which furthercontributes to the prevention of premature discharge. The pressureprevailing in the chamber 19 can no longer have the effect that thepiston 23 moves further, so that said pressure is entirely used fordischarging cleansing medium, via chamber 19, access 26, duct 31, littleduct 32 and finally discharge opening 29 in the direction C, towards theteat cup 5. The piston 23, a kind of sliding cock as it were, herecompletely closes off the passage 15, so that there is no danger thatcleansing medium ends up in the milk line 6. The fitting of the pistonbetween the grooves 21 and the cavity 23 is so snug, thatthe—intended—operation movement of the piston is possible, though thatleakage of liquid past the piston is prevented.

Then the teat cups are removed from the teats but the pressure in line 9is still maintained, until the milk cups are situated in hangingposition, so that the cleansing liquid can leak out of the teat cups.

After a short while the pressure in the line 9 is released, after whichthe piston 23 can move again to the initial position, the milkingposition, under influence of a spring 25, which under the influence ofthe pressure in the chamber 19 was kept pressed in between the flange 24and the ring 33. Instead of the spring 25 the line 9 can be put onvacuum B′, in order to thus, as it were, suck back the piston 23. Duringmilking said vacuum B′ is then maintained.

The coupling piece 104 shown in FIGS. 4A-C corresponds to some extent tothe coupling piece 4 discussed above, though differs from it on somepoints. As can be seen in FIG. 4A there is question here of a housing114 made of synthetic material, having a passage 115, a connection end116 and a discharge end 117. A circular collar 139 is formed on thehousing 114, the collar having a passage 170 that is transverse to thepassage 115 and is in open connection to it. The passage 170 is limitedby a shoulder 133 and an edge 134 above it, on which a sealing ring 122is placed. Said sealing ring 122 is further shown in FIG. 4B, and has anouter ring 156, which to the inside merges in a wedge-shaped lip 155that is formed as a unity with it. The ring 155 is able to deform in thedirection M for the sealing. The ring 122 is made of suitable rubbermaterial, in which metal reinforcement rings 156 a and 156 b have beenintegrally formed. The top side of the ring 156 forms a shoulder 161, onwhich a metal support ring 160 may come to lie. Said metal support ring160 forms a stop for the pressure spring 125 (FIG. 5A), and alsoprotects the ring 122 against damage by the spring.

The housing 114 is furthermore provided with a transverse guidance 140,that is formed complementary to the free piston 123 yet to be discussed.Said recess 140 is situated at two diametrically opposite sides of theinner wall of the passage 115. In the wall portion that is situatedopposite the passage 170 a shallow recess 120 is formed, foraccommodation of the end of the piston 123, in the cleansing position.

The free, in this example substantially straight circle cylindricalpiston 123 is provided with a duct 131 extending in axial direction,that is turned at right angles to a little duct 132, that ends indischarge opening 129. In the widened inner end 123 a of the piston 123a shoulder 151 is formed in the duct 131, for accommodation of an O-ring152. Above it a passage 150 is situated, in which pin 127 yet to bediscussed can easily be inserted. At the circumference of the widenedinner end 123 a of the piston 123 a shoulder 185 is situated and aboveit a circumferential groove 152, in which an O-ring 153 is placed. Ascan be seen in FIG. 4A the piston 123 has a narrowed portion 123 b belowthe widened inner end 123 a. In the narrowed portion 123 b, at one side,at the side where the sealed opening 129 is situated, a flat surface 180is arranged forming a recess with respect to the circumference of thenarrowed portion 123 b.

In the upper part of FIG. 4A the extension 118 is shown forming astraight circle cylindrical chamber 119, and at the lower end or outerend being provided with a collar 138, that snugly fits the edge 134 alsolying on support ring 160. The extension 118 can be glued to the housing114 and/or by means of screws (not shown) that are to be inserted intoholes 163 a,b.

Fixedly attached in the extension 118 is a pin 127, forming a continuousduct 127 a, that is in communication with the supply hose 109 a, for, atchoice, compressed air, water and cleansing medium, such as iodine. Ascan be seen in FIG. 4C said line 109 a ends in connection 130 aeccentrically with respect to the chamber 119, and thus the pin 127 isalso eccentric, just like in the example discussed earlier. A differencenow is that here a separate line 109 b is present for compressed air,with which in the assembled situation, a delivery pressure can be put onthe top side or inner side of the piston 123—via centric connection 130b—, for axial movement of the piston 123. Said pressure hits the innersurface of the widened head 123 a of the piston 123, and said pressurecannot leave as a result of the O-ring 153.

At the opposite side the extension 118 is further provided with drainageholes or drainage slits 141 a, 141 b, that open in the free atmosphere.

In FIG. 5A the situation immediately after milking is shown. The lastmilk has flown down in the direction A. Then compressed air from thedirection D is supplied via line 109 b, as a result of which, for theabove-mentioned reasons, the piston 123 is urged in the direction F.Guided by the guidances 140 the piston finally arrives with its end inshallow recess 120, and because of the snugly fitting design the passage115 is then closed off, in correspondence with the situation of FIGS.2B/3B.

The situation shown in FIG. 5B is then achieved, and when the milk lineis still attached to the teat of the cow via the teat cup, whilemaintaining the pressure in line 109 b, a mixture of air and cleaningmedium can be discharged via line 109 a in the direction E. This thenarrives in pin 127 via the duct 127 a, through O-ring 152, withoutleakage in duct 131, in little duct 132 and finally said mixture comesout of discharge opening 129 in the direction C, forcefully to the teatand the teat cup.

Special now is that moisture falling back, in which iodine might bepresent, may fall on the portion of the piston 123 extending in thepassage 115, in the direction G, but that as a result of theshort-circuiting made by the flattening 180, said moisture can go pastthe lip 155 in the direction N, to the space 181 that is present betweenthe narrowed portion 123 b and the wall of the extension 118. Thedistance between the widened portion 123 a, in particular the O-ring 153and the piston end on the one hand and the distance between the drainageholes 114 a,b with respect to said same end is such that a leakage pathremains and the residual moisture can get to the outside via thedrainage holes (arrow H). Here the moisture is able to flow around thenarrowed portion 123 b of the piston. Thus it is (further) counteractedthat cleansing medium ends up at the other side, the milk collectionside, when retracting the piston.

After the cleansing medium is discharged in this way the pressure inline 109 b is maintained, and as is shown in FIG. 5C, a pulsatingmixture of water/air is discharged in the direction E. The teat cupshowever have been disconnected then, as a result of which they will hangdown. The coupling piece 104 will therefore be inverted with respect tothe FIGS. 5A and 5B. The rinsing medium flows in the direction 1,through the duct 127 a in the pin 127, through the ducts 131, 132 andflows out in the direction J, downwards through the discharge opening129. In the direction K the rinse water can continue its way to rinsethe connected teat cup.

After that the pressure is lowered on the line 109 b, so that under theaction of the spring 125, on the one hand supporting against shoulder185 at the widened inner end 123 a of the piston 123 and on the otherhand supporting against the ring 160, again entirely to the inside, sothat the passage 115 is entirely free again. Special now is that rinsingwater can be supplied in the direction E through the duct 109 a, whichrinsing water flows via the pin 127 then accommodated in the duct 131,the pin 127 being short enough for the rinsing water to enter the littleduct 132, in order to come out in the direction L and then flowingaround the narrowed piston portion 133 b and the spring 125 to finallycome out through the now lowermost drainage hole 141 a in the directionM. The sealing ring 122 with lip 155 here ensures that no rinsing waterwith possible iodine residues ends up in passage 115.

After that, the pressure is released from the line 109 a, and thesituation shown in FIG. 5A is achieved, in which milking can take placeagain. During milking, the lip 155 ensures that as a result of thevacuum in the milk line, no possible residues can get from the chamber1119 in the passage 115.

In the alternative embodiment shown in FIGS. 6A-D a coupling piece 204is first shown in FIGS. 6A,B having an input end 217 situated at theteat cup side and an end 216 leading to the milk collection chamber, inwhich coupling piece a milk passage 215 is formed.

The coupling piece 204 has a circular cross-section at the ends 216 and217, which however in the cross-section of FIGS. 6B,D taper with walls292, 293, and in the cross-section in FIGS. 6A,C flares of towards themiddle of the coupling piece 204. The walls 292 and 293 there merge in atruncated conical space, formed by cone walls 294. A truncated conicalclosing body 223 is accommodated rotatable about its centre line andsnugly fitting in said conical space. Said closing body 223 has an innercavity 290 limited by wall 296 in which two holes 291 a, 291 b areformed that are situated diametrically opposite each other. As canclearly be seen in FIG. 6C a duct 227 extends through the closing body223, which duct is connected to a line 209 for compressed air/cleansingmedium, and possibly water. The duct 227 is turned at right angles inorder to debouch in passage 215 at the location of the discharge opening229, coinciding with the centre line of passage 215 and directed towardsthe end 217.

The closing body 223 is attached in the coupling piece 204 with suitablemeans, such as for instance a threaded end/bolt, washer connection,against movement along its centre line. Other means, and sealing ringswhere needed, can be provided. This embodiment is meant to beschematically shown.

In the situation shown in the FIGS. 6A,B, milk can flow in the directionA of the teat cup, through the passage 215, through hole 291 a, space290, hole 291 b and further to a milk collection point.

When milking is completed the closing body 223 is turned in thedirection P over 90° by means of remote controllable means that are notfurther shown. Then the situation shown in the FIGS. 6C,D is achieved,in which the discharge opening 229, which in the situation of the FIGS.6A,B is either shielded or closed off by the cone wall 294, has beenreleased and lies in the centre line of the coupling piece 204.Compressed air with cleansing medium is then supplied in the direction Rthrough line 209, and squirts in the direction S out of the dischargeopening 229.

1. A device for pneumatically milking a cow, comprising a number of milkextractors, each comprising a teat cup as well as a milk line connectedto the lower end of the teat cup, said milk line leading from the teatcup to a collection chamber for discharging the milk from the teat cups,the device being provided with a supply for a cleansing medium to theteat cup for each milk extractor, in particular to a teat present in theteat cup, the supply comprising a supply line having an end portion withdischarge end, and each milk extractor being provided with a closingbody for closing off the passage of the milk extractor at or downstreamof the discharge end of the line for cleansing medium when the cleansingmedium has been discharged through the outlet and into the milkextractor, the closing body is movably mounted in a chamber debouchinginto the milk extractor and movable between a position leaving thepassage of the milk extractor open and a position closing it off, theclosing body being provided with a squirt line forming the end portionwith the discharge end for the line ensuring the supply of cleansingmedium and being positioned to debouch into the milk extractor and theclosing body having a fluid connection between the space in the milkextractor upstream of the closing body and the chamber when in theclosing position.
 2. A method for milking a cow comprising the steps of:closing the milk discharge after milking by moving a closing body from aposition keeping the milk discharge open to a position keeping the milkdischarge closed; discharging cleansing medium via the closing body bysquirting in the milk a discharge towards a teat cup; releasing the teatcups while keeping the closing body in the closed off position; asquirting a pulsating water/air mixture via the closing body for rinsinga milk extractor; and when the teat cups are still attached to the cow,in the closed position of the closing body, allowing draining back ofcleansing agent to be deflected from the side of the closing body facingthe teat cup to a chamber.